These little balls are used as a pair. Yamuna first developed them for runners, cyclists, dancers, and climbers to work their knees, calves, and ankles. You can also use them to roll up both sides of the spine at the same time. Most exciting: they're our yoga balls. Applying the black balls at tight points of individual tendons and muscles, you can master even the most difficult yoga postures.

Please note that the pump shown on the image is for illustration purposes and it is not included with the kit.